The mathematical model of the Hengsha port area in at Yangtze Estuary is built based on the CJK3D-WEM model to study the changes of hydrodynamic force in water around the port after construction of Hengsha port.The result shows that after the implementation of port Hengsha scheme,the diversion ratio of each section has small changes.In the south channel,the fluctuating velocity in upper north channel increases to some extent,and that in the downstream north channel decreases slightly.The ebb current in the South-North Channel changes slightly and still shows obvious ebb along the north.The ebb velocity change is small,the maximum flood increases in north port estuary,and the remaining section decreases.The implementation of the project has a small influence on the river regime of the Yangtze Estuary sandbar area.